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Developmental timing of transgene expression is dosage dependent
Author(s) -
Bucherándor,
Thyge Okkels Finn,
Palmgren Gorm
Publication year - 1999
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1999.100113.x
Subject(s) - biology , gene silencing , cauliflower mosaic virus , transgene , gene , gene dosage , genetically modified crops , gene expression , southern blot , insert (composites) , genetics , reporter gene , microbiology and biotechnology , mechanical engineering , engineering
Expression of a β ‐glucuronidase (GUS) gene ( uidA ) driven by the cauliflower mosaic virus 35S promoter was studied during development in progeny from a primary transformant of tobacco carrying 3 independently segregating inserts. In the R1S2‐generation, plants could be grouped to 4 GUS expression phenotypes, showing either continuous GUS activity [S(‐) plant] or silencing of GUS after 13, 5 or 2 weeks [S(13), S(5) and S(2) plants, respectively]. In S(13), S(5) and S(2) plants, GUS activity was reduced 7‐, 17‐ and 50‐fold, respectively, as compared to the S(‐) plant. Southern blot and segregation analysis showed that S(2) plants contained all 3 inserts of which at least 1 was homozygous. All S(5) plants contained 2 inserts, 1 of which was homozygous and the other hemizygous. The S(13) plant contained 2 hemizygous inserts, while the S(‐) plant contained 1 hemizygous insert. Analysis of the R1S3‐generation showed that the timing and degree of silencing was directly linked to copy number and that each of the 3 inserts seemed to contribute equally to gene silencing. The physically linked neomycin phosphotransferase II gene driven by the weak nopaline synthase promoter was also subject to dosage‐dependent gene but this occurred later and was less pronounced.